Egoism holds we ought to do what is in our own interests. What is in my interest is largely determined by me.
Suppose Isabel wants to acquire the most advanced credential in Biomedical Engineering (BME) research. The ethical egoist has no problem explaining why Isabel should act in accord with the rules of the BME profession. The explanation goes as follows.
1. Isabel desires to earn a doctorate in BME.
2. To earn a doctorate in BME, one must follow the rules of the BME profession.
3. Therefore, Isabel should follow the rules of the BME profession.
Egoistic reasoning of this sort is instrumentalist insofar as it focuses attention on the intermediate steps, the "instruments," necessary to achieve one's own ultimate objectives. Egoistic reasoning is also internalist insofar as it focuses attention on reasons each of us actually has: "internal" reasons, as it were.
What happens when our interests conflict? Suppose Isabel walks into the lab one day and finds herself with a strong reason to drop some data points. She has worked for months on an experiment, has not gotten the results expected, and must finish her report today so her mentor can finalize the paper he must present at a conference next week. Isabel has two conflicting interests: drop the points to produce the "right" results versus include the points to obey the professional rule.
When your interests conflict, the egoist advises, you must decide which action will serve your overall best interests. If your deepest desire is to become a credentialed BME researcher, you probably should decide to follow the rules. If your deepest desire is to please your mentor, perhaps you should break the rules. In either case, you must decide the right thing for you to do.
For the egoist, wrong actions are imprudent, irrational, and frustrate ourselves in trying to achieve the things we most want to do. Right actions are actions that assist us in achieving our dearest objectives. In ethical decision-making, therefore, egoists recommend this rule: